Electric motor.



8I G. LM WIE,

ELEGRIC MOTS@1 APPLIcAmN mi@ 1M. 2e, mo.

Patente Aug'. 31, 1915.

4 SHEETS-SHEET 11 INVENTOR wm@ 15; WMM

ATTCRNEY B. G. LAMME.

I ELECTRlc MOTOR.

Patented Aug'. 31, i915.

4 SHEETS-SHEET a.`

B. G. 4LAI/WIE.

ELECTRIC MOTOR.

APPLICATION FILED IAN. 2b` 1910.

Patented Aug. 31, 1915.

4 SHEETS-SHEET 4.

WITNESSES:

onrrsn BENJAMIN G. LAMVIE, 0F ITTSBUBGH, PENNSYLV ill., ASSG'NOR TO UVESTNG HOUSE ELECTRIC AND MANUFACTURING COJKJNY, A CURPGRATIGN 03? PENN SYLVA'NI.

i Application filed January 3553.9.

To all whom it may concern Be it known that l, BENJAMIN G, LAMM'E, a citizen of the United States, and a resident otPittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful lmprovement in Electric Motors, of which the following is specification.

My invention relates to electric motors and particularly to such motors as may be operated by either alternatingor direct currents.

The object of my invention is to provide a motor having such structural and electrical characteristics that if may be operated etticiently by either alternating or direct currents.

.Electric railwv equipped with 'Y :f vehicles are frequently pelling motors that may be supplied with L ther alternating or direct currents in orde.:v iat they may be operated over existing direct current railway systems in cities or towns, and over alternating cur- -rentsystems in rural and inter-urban districts Where it is more economical to trans mit the power over the longer distances by means of highvoltage alternating current, the transmission voltage, in the latter case, being reduced upon the vehicle to that which is suitable for application to the motors. For the most advantageous operation oiE the motors by alternating currents, the voltage applied thereto should not exceed haii2 that 'of most direct current systems, so that, .passing from a direct current an altermating current section of a system, or vice versa, it isnecessary, or at least desi "able, to change'the voltage which is applied to the v motors.

According to the present invention, a motor is-so lce[nstructed and its circuits are so controlled that, for the saine speed and eld strength, a higher voltage may be applied theretor when it is operated by direct current than when it is operated by alternating current,`and the most economical and elticient conditions of operation may be sec` rod with each character of current. in order to etieet this result, vthe motor is provided with a larger number of iield poles when it sup plied with alternating current than when it is supplied *ith direct current, and also with a ring armature that readily permits oi: such a change in the number of poles.

motor is further 'nr-ovided with aurili Specification of Letters .atent.

i rent operation, and Fig. v3 is a similar Fat-,enteral Ango 3i, l.,

serial no. 540,185.

afindinCr for neutralizing the armature reaction, tile said Winding being so arranged that it is eective Jfor both numbers of iield poles. The change in the number of :field poles causes greater amounts of flux to traverse certain portions oi' the field yoke "with the smaller number of poles than traverse the said portions with the larger number of poles, and 'the said portions are, accordingly, made of larger cross-sectional area than the remaining portions of the field yoke. llor certain conditions of operation, it may be desirable to provide .for greater field strength in the motors for direct current operation than for alternating current operation, such provision being also made accord ing` to one modifica tion of my invention..

lti'y invention illustrated in the roce-ny panying drawings, ig'ure l of which illustrates, diagrammatically, a motor einbodying my invention, with means for changing' its circuit connections to adapt it for operaH tion by either alternatirng1 or direct currents. Fig". 2 is a simpliied diagrammatic vieu' illustrating the connections of the main iield Winding whenarranged for alternatingcui'u W oi said Winding when arranged iter direct current operation. Fig. Zlis a simplified diagrammatic view of the auxiliary or neutralizingp winding ci the motor when ar vLfig. d i g embodying' a modifica on of i on th means for'arrangi .0' its it connections for either alternatin or direcJ current opintion. Fig. Y is a simnniatic view ot' the main field f 't S when arcurrent operation, i ien' of the said vrinding c .on :tor direct current operation.

'lli eid magnet frame )rejections 9 to 13, .tively provided .Y Y

. .in with C 4- o or alternat or direct cur-- m25-, inclusive,

are connected in series in two sets that re spectively comprise the coils on alternate pairs of poles. The successive coils of each set are arranged to cause thecorresponding poles to loe oi opposite sign or polarity.

A common terminal 27 of the two sets of coils is connected to a stationary contact terminal 28 of controller 29, whereby the circuits of the motor may be readily adapted for operation of the motor by either alternating or direct currents, and the remaining terminals 30 and 3l of the two sets of lield coils are respectively connected to stationary contact terminals 32 and 83 of the controller.

The controller 29 comprises, in addition to a. set of stationary contact terminals, two sets 3i and 35 oi movable conducting seglnents that are adapted to engage the sta.- tionary contact terminals, the circuits of the motor being arranged for alternating cur rent operation when the segments 35 upon the line A-(l engage the stationary Contact terminals, and for direct current operation when the segments 3l: upon the line D-O engage the stationary contact terminals. Thus, for alternatiiigcurrent operation, the two sets of field coils are connected in parallel relation, as indicated in Fig. 2, and the arrangement is such that adjacent polar projections are oi' different polarity. rlhe field, accordingly, has twelve, or its maximum number of poles. For direct current operation, however, the two sets of lield coils are connected in series elution, landere so arranged that the poles produced by alternate pairs oli coils, viz., 4t, 5; 8, 9; and l2, 13 are reversed and of different polarity from those produced when the coils are connected for direct current operation. jections S, 4t; l', S; and ll, l2 are of the same polarity, and the remaining' poles are of opposits polarity, the total number of poles he lng six, or just half the number oli poles em 5 ploy/ed for alternating current operation.

The latter arrangement ot the coils is clearly shown in l? 3,

The lield iframe is also provided with an auxiliary winding for neutralizing the ar- `ture reaction, which winding consists of sin' groups of coils 3G, 3'?, 38, 39. Zl0 and Ll-l, the side or Inductor portions oi which are located in slots at the extremities of the ar projections, and the end portions oit ch connect all of the inductor portions polar projection to all of the inducftions in one oit the adjacent polar proations. ln this respect, the arrangement #of the coils is novel., since, in structures heretofore provided, one-halt of the. coils associated with each polar projection extend therefrom to the next adjacent on one side, and the other hall1 extend the next adjacent upon the other side.

or p

rlhus, polar prowith the present arrangement, the neu-v tralizing winding may be readily and conveniently connected so that it will be eiiective with both numbers olf lield poles, will be explained presently, whereas, it could not be done if the winding` were arranged in the customary manner. The coils of the neun tralizing winding are arranged in two sets, the one set comprisinp groups ol coils 36, 38I and Ll() and the other set comprising groups of coils 3"?, 39 and -l-l.

. A common terminal ll2 of the two sets ci. coils is connected to contact terminal of the controller 29, and the remaining terminals 4.4.- and .l5 thereof are connected, respectively, to Contact terminals 4G and 4:7 of the controller 29. The construction of the controller 29 is such that when the segments 35 upon the line Amt) engaee the stationary contact terminals-under which condition the circuits are arranged i'or alternatingcurrent 0peration-the two sets of coils of the neutralizing winding' are connected in parallel relation, asv illustrated in a simple manner in Fig. 4. YWhen the controller segments 34 in the line D-C engage the stationary contact terminals-under which condition the circuits of the motor are arranged for direct current operationhtlie coils oi the neutralizing windingn are all connected in series, the current being.' reversed in the grou ps of coils 37, 39 and el. 'from the direction in which it traversed the said coils when the circuits of the motor were arranged for alternating our t operation.

Since, as hereinafter explained, the volt age applied to the motor for alternating current operation is approximately one-halt that applied thereto lor direct current operation, for the same output of the motor, the armature current tor alternating' current operation will be double that for direct current operation, and., consequently, the current traversing' the neut alizing winding, which is connected in series with the armature, will be one-h allfm' direct current operation, what it is tor alternating current oporation. The ampere-turns or dcn'iagnetizing cll'ect of the neutralizing winding should, of course, be the same. irrespective of the voltage applied to the motor, and it is lor this reason 'that the two olf coils oiE the neutralizing` winding are connected in par-- allel relation for alternating` current operation and in series relation for direct current operation.

The armature 2G provided with a winding' i8 that is connected, by means olE suitable resistance leads 4.9, to the segments of a coimnutator cylinder 50, upon which bear three sets ol? brushes 5l to 62, inclusive, one comprising alternate brushes 5l, 53, 5o, 5?', 5S) and Gl, the second set comprising brushes 52, 5G and GO, and the third set co1nprising brushes al, 58 and 62. lrushes 5l, 53, 55, 5T, 59 and Si ol the Afirst set are so located as to be ineective when the circuits of the main ield magnet winding are arranged to produce the smaller number of poles, z'. e., for direct current operation.

The brushes of the respective sets are con nected together, and the vfirst set is connected .to stationary contact terminal 63 of the controller 29, the second set to stationary conof the first set-constitute one terminal et' the upon the line D'-C engage the stationary contactrterminals, the brushes 51, 53, 55, 57, 59 and 61 of the first set are not connected with other parts, and the other two sets of brushes severally constitute the terminals of the armature circuit. Under this condition., the field has the smaller number et poles, and the counter'electromotive force of the armature is that generated in the portion ot its Winding which extends between alternate commutator brushes. With the same field strength andfspeed for both direct and al ternating current operation, the counterelectromotive force of the armature will, accordingly, be greater for direct current than for alternating current operation, and the voltage applied to the motor should be Idouble for direct current operation what it is for alternating current operation.

The controller 29 serves not only to govn ern the circuit connections of the various windings of the motor, but it also serves to connect the said windings all in series, ooth for alternating and direct current operation, and .to connect the mot`or either to a suitable source 66 of alternating current or te a source ei direct current, according as the movable segments thereof upon the line ifi-C or the line DWC engage the tionary contact terminals, it being stood that the alternating current voltage is usually lessl than, or approximately one-half, the direct current voltage.

With the `main field coils arranged as illustrated 'in i, the cmpereturns or mugnetizing eiicct of the lieid wine1 s will be the same ier both alter' ating anu direct current operation, since the held current for alternating current operation is double that for direct current operation, whiie the "cts oi ield coils are changed from paralisi lation, for alternating current operation,

series relation for direct current operation, and the alternating current voltage is ap proximatcly halt the direct current voltage. lhe iield iiux, therefore, is the same Afor both alternating and direct current opera tion, but the amount that will traverse the yoke of the iield trame between polar projections .2 and 3, 4 and 56 and 7, 8 and 9, 10 and l1, and l2 and 13 ,will be twiceas much for direct current operation as for alternating current operation. in order that the reluctance of these portions of the magnetic circuit may not be excessive for direct current operation, they are increased in cross-sectional area, the remaining portions being only oit' suilicicnt cross-sectional area to carry the I'iux for alternating current operation. 'lhe eld structure is therefore elD the minimum dimensions for eii'ectivc operation.

in order to permit of opening the field fame for the removal of the armature or for other purposes, it may be split in a plane indicated by a line GS, which passes throng the field iframe between the polar projections where the yoke is of the smallest cross-sec tional area, there being no flux in these parts during direct current operation. With the coils of the neutralizing winding arranged as illustrated, the frame of the motor may also be opened without severing or disconnecting any ot' the said coils.

For certain conditions of operation, it

Cri

may be 'desirable to provide a field for direct current operation that shall be double that provided for alternating current operation, and, in Fig. G have shown a motor'provided with a field winding adapted to produce this result, together with a controller for properly arranging the field connections. ln. this motor, the field coils are arranged in four sets, in auch of which the coils are connected in series, the iii-st set comprising coils 70, 7l and 72, the second set, coils 73, 74 and 75, the third set, coils 76, 77 and 78, and the fourth set, coils 79, 8O andl. `For alter nating current operation, the segments of the controller that lie upon the line Af-C., engage the stationary contact terminals ther-coi, and the armature, the neutralizing winding and the field coils are all connected. in series relation, in Fig. l, but 'the .teur otiield coils are connected. in parallel relation in such manner that adjacent iolar projections are orf dilierent polarity, as illustrated in Fig.v 7. 'lhe field then has twelve, or the maximum number of poles.

dire@ current operation, the segments o c t lie upon the line 'lli- Q, en y v l, contact terminals, and the Lour sets oi iield coils are then connected in series relation, rthe current being reversed in coils 73, Ti. 75., 7i), S() and 8l, so that the :pending poles are oi? one polarity and the remaining are ot the opposite SiS pclarity9 there heling sin poles in llt the direct current voltage is double the elternating current voltage, direct current will be heliE the alternating current for the same pow r. All of the coils are in series,

however, Whereas, for alternating current and a commutator? of means for producinga greater number of field poles for alter-nat-` ing current operation than for direct current operation and. for connecting either et the sources of current to the armature Winding tilrough said ccmnfuitator,

Q.. rEhe combination with a dynamo-electric machine adapted for operation by either alternating or direct currf-Jnts7 comprl ing' a dheld magnet structure, a main NiniA ug ther-eter`r an armaturewinding, a neutraliif1 ing Winding and a con'unutatcr, of means for arranging Lain Winding to 'e educ-e fr nuinlm: of poles 'for alte cur oper tion than for direc *c opera tion, 'for arranging the neu finding to be effective `.to/r either er of poles and for connecting eitlu oiL the sourcce of cur rent to said armature 'winding thi-ou 7aid commutator.

3. in a dynamde L. for operation by ei-L ating or o irect currents, the comb ration 'with a ield magnet structure haring polar projections, main Winding surroiuiding the 'polar projections, and an auxiliary winning e ending 1oetween the polar projections, or means tor adjusting the connections of the main wind ing tu produce a greater nunilier field poles for alternating current'operation than tor dir ,ct cir 'ent operation, and to render the aixiliary winding cii'ective ii'or either number et poles.

il?. d dynamo4 electric machu e afiior operation v ci ther alterna currents comin l l ture and ineens f' direct current operai The meti an electric direct cur rents which cons t to the motor a higher alternating 'tha motive torce, in producingY a greater number of field "soles in the ui for alternating' current operation than ,tor direct.

direct clectre- -current operation and in commutating the armature currents for both conditions of operation.

6. llhe method of operating an electric motor by either alternating or direct currents which consists in producing in the motor greater number of field poles of less strength for alternating current operation than tor direct current operation.

3; The method of operating an electric motor by either alternating or direct currents which consists in commutating the armature currents for both conditions of operation, and producing a greater number of. iicld poles in the motor for alternating current operations than for direct current operationn 8, The method of operating an `electric motor either alternating or direct currents which consists in commutating the armature currents for both conditions of 0peration, and cl. anging the connections of the held magnet Winding of the motor to produi; a greater number of field poles in the motor for alternating current operation 'than for direct current operation.

9. 'Che method of operating an electric motor having a plurality of ield coils by either direct or alternating currents which consists in commutating the armature currents for 'both conditions of operation, and connecting` the held magnet coils in series for direct current operation and in parallel to produce a greater number of i'ield poles for alternating current operation,

l0, The method. of operating an electric motor having a plurality of field magnet coils by either direct or alternating currents which consists in connecting the coils in series for "ircctcurrent operation and in parallel to produce a greater number of field poles of less strength for alternating current operation.

1L The combination with a dynamo-electric machine adapted for operation by either alterna-ting or direct currents and having a plurality of field magnet coils, an armature, anda commutator, of means for connecting the said coils in series relation for direct current operation and in parallel relation to produce a greater number oi field poles for alternating current operation, and for connecting. the commute-tor in series with 'the source of current under both conditions o operation.

l2. 'lll-e ccmbirnition with a dynamo-elec i .ptcd for operation by either i direct currents and having a pluralitj,y o field magnet coils, an armature, and a 1 nnmutat u, of means for connecting .the :wid coils in series relation for direct series with the source of current under both conditions of operation.

13. A dynamo-electric machine adapted for operation by either alternating or direct currents comprising series-connected ieid magnet and armature windings, and means for arranging the field magnet windino to produce a greater number of field poes for alternating-current operation than for direct-current operation.

14. A dynamo-electric machine adapted for operation by either alternating or direct currents comprising series-connecting field magnet and armature windings, and means for arranging the field magnet winding to produce a greater number of field poles of less strength for alternating-current operation than for direct-current operation.

l5. The combination with a dynamo-electric machine adapted for operation by either alternating or direct currents, comprising iield magnet and armature windings connected in series, of sources of alternating and direct currents, and a controller for connecting said windings to said sources of current and for arranging the field magnet windings to produce a greater number of poles for alternating-current operation than for direct-current operation.

16. The combination with a dynamo-elecinsee tric machine adapted for operation by either alternating or direct currents, comprising seriesconnected field magnet and armature windings and a commutator, of sources of alternating and direct currents, and a controller for connecting either of said sources to said windings through said commutator and for controlling the number of poles produced by said field magnet winding in accordance with the source to which the windings are connected.

17. The combination with a dynamo-electric machine adapted :for operation by either alternating or direct currents, comprising series-connected held magnet and armature windings and a conirnutator, of sources of alternating and direct currents, and a con.- troller for connecting either oi said sources to said windings through said commutator and for simultaneously controlling the number or' poles produced by said field magnet winding in accordance with the source to which the windings are connected.

in testimony whereof, have hereunto subscribed my name this 19th day of J an., 1910.

BENJ. G. LAMME.

iNitnesses:

E. Livrncs'ronn, id. B. Hiuns. 

